The ISB6.7 G is based on the Cummins ISB6.7 diesel engine platform and will operate exclusively on natural gas – either compressed natural gas or liquefied natural gas. The engine is currently in field trials and will have a range of ratings of up to 260 hp and 660 lb.-ft. of torque and automatic transmission capability that can be specified to customer and OEM requirements.

The ISB6.7 G features three-way catalyst aftertreatment that's packaged as a muffler and requires no maintenance, according to Cummins Westport. No diesel particulate filter or selective catalytic reduction aftertreatment will be required.

The engine is expected to be certified at launch to meet the U.S. Environmental Protection Agency and California Air Resources Board emission standards and 2016 U.S greenhouse gas and fuel economy regulations. The ISB6.7 G will be manufactured in Cummins' medium-duty engine plant in Rocky Mount, N.C.

Fiat Chrysler Automobiles and a German auto supplier have agreed to settle claims and lawsuits arising from the 3.0-liter V-6 diesel engines installed in 104,000 Jeep Grand Cherokee EcoBoost and Ram 1500 EcoBoost models sold in the U.S. in the 2014 to 2016 model years.

Tacoma and Clark Public Utilities in Washington as well as the city of Palo Alto, Calif., are the latest West Coast municipalities and utilities to electrify portions of their fleets with XL-equipped vehicles.